1. Technical Field
The present invention relates to a technology of printing a character with high quality in a printing apparatus.
2. Related Art
In a printing apparatus, various colors can be output by utilizing a combination of C-, M- and Y-color inks. For example, a blue color can be output by utilizing a C-color ink and an M-color ink, and a red color can be output by overlapping and outputting the M-color ink and a Y-color ink. In addition, a black color can be printed by overlapping the C-color ink, the M-color ink and the Y-color ink by the same amount. By utilizing the combination of the C-, M- and Y-color inks, various colors can be output.
Meanwhile, in such a printing apparatus, if a black character is printed by overlapping the C-, M- and Y-color inks, the amount of ink is large. Thus, the ink may be oozed and thus the character may be blurred. Therefore, a technology of printing a character without blurring by mounting a black color ink (K-color ink) in addition to C-, M- and Y-color inks and printing the character using only the K-color ink is developed (JP-A-10-200769).
However, if the character is printed using only the K-color ink, printing quality may deteriorate by revealing a background color of a printing sheet. That is, if printing is performed using only the K-color ink, since the ink amount is reduced compared with the case where the printing is performed using three-color inks of C, M and Y, when a hitting position of the ink is slightly deviated, the deviated part is not covered by the ink and the background color of the printing sheet remains. Accordingly, the background color of the printing sheet is revealed at some places of the character and thus printing quality may deteriorate. The K-color ink and the C-, M- and Y-color inks may be combined. However, in this case, since the C-, M- and Y-color inks are utilized, a character with blur impression is susceptible to be obtained. In addition, since the K-color ink is utilized, the hitting position of the ink may be deviated and thus printing quality may deteriorate. Accordingly, this is not an efficient solution.